[m-rev.] for review: move char_to_doc to pretty_printer.m

[Peter Wang]

On Mon, 19 Dec 2022 23:48:14 +1100 "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> For review of the idea of moving x_to_doc functions to pretty_printer.m.
> If approved, I would move all such functions to pretty_printer.m,
> leaving obsoleted forwarding functions behind. When we delete
> these later, one cause of circular .trans_opt dependencies
> will have its applicability domain significantly reduced.
> Specifically, it should get rid of the dependency of
> modules defining functions such as float_to_doc and uint_to_doc
> on pretty_printer.m, though the dependencies of modules
> defining operations that convert compound values such as
> arrays and bitmaps to docs on pretty_printer.m would remain
> in cases where the required types and access predicates
> are not exported to pretty_printer.m. This would be the case
> e.g. for tree234_to_doc, unless e.g. we export tree234_to_lazy_list
> (in a non-public interface) to pretty_printer.m.

That's fine.

Peter